A KDF is a Key Derivation Function. A KDF is used within the field of cryptography to generate one or more keys from a seed value. This seed value could be a password or the secret generated by a Diffie Hellman key derivation function. Well known KDF's are crypt, bcrypt, scrypt, PBKDF2 and HKDF. The Password Based Key Derivation Functions are commonly used to securely hash a password using an iteration count and a salt.
